This invention relates to the art of collapsible dispensing containers and, more particularly, to a laminated tube structure for the body of such a container and a method of making the tube.
Collapsible tubular containers are provided for dispensing a wide variety of products including, for example, cosmetics, shampoos, foods, dentifrices and the like. Problems encountered in connection with oxygen absorption and product contamination and permeation have led to considerable efforts to provide laminated constructions for the body portions of the dispensing containers to overcome the problems. Such laminated constructions generally include a barrier layer of metal foil to eliminate oxygen absorption and water vapor transmission and inner and outer layers of a thermoplastic material such as polyethylene. The inner layer of polyethylene protects the product from contamination by the metal foil but, while such inner layer can be made relatively thin, an undesirable degree of product permeation still takes place causing deterioration of the product in the container. Heretofore, the tubular body portions of such containers have been produced by forming a flat laminate into tubular form with overlapping edges and then heat sealing the edges to provide a tube having a longitudinal seam. Such a heat sealed construction necessitates heat sealing compatibility of the inner and outer layers of the laminate and thus requires both layers to be thermoplastic. Accordingly, such previous methods of construction limit selectivity of materials and thus limit the use of containers employing such body constructions. Moreover, the compatibility requirements for heat sealing have made it impossible to employ thermosetting plastic materials for the inner surface of the tubular body so as to minimize the product permeation problem for the inner layer of a container.
With further regard to such previous container body constructions, the longitudinal seam produced by heat sealing the laminate edges creates problems with respect to providing indicia on the outer surface of the tubular body. In this respect, such a longitudinal seam makes it necessary to pre-print the plastic film defining the outer layer of the laminate by rotogravure printing methods. More particularly, the presence of a longitudinal heat sealed seam in the tubular body portion provides an interruption in the otherwise circular outer surface contour of the tube, whereby the tube cannot be printed upon after formation thereof by less expensive techniques such as roll printing. Still further, such a longitudinal heat sealed seam is visible and, accordingly, is undesirable from the standpoint of aesthetics.